CHICAGO -- The little electrical shocks that Wen Li gives subjects at her Northwestern University neuroscience lab feel less painful than a bad jolt of static electricity, and more like the mild snap of a rubber band on skin.
But getting just seven of those little shocks trained people in a new study to distinguish between extremely similar odors, offering a new and perhaps potent way of changing a person's power of perception. Psychologists have used the basic conditioning technique for decades to alter the behavior of people and animals. But experts said the Northwestern study went further by actually modifying how the brain processes the sensation of smell.
The new report, published in Friday's issue of the journal Science, illustrates the power of emotions like fear to shape how we learn and even perceive the world, said Dana Small, a neuroscientist who studies odor and taste at the John B. Pierce Laboratory in New Haven, Conn.
The findings may reveal some of the tools that evolution has given humans and other creatures to adapt quickly to new surroundings and sensations, said Li and one of her co-authors, Northwestern researcher Jay Gottfried.
In nature, an animal's survival might depend on learning the difference between two similar scents say, the smell of an ordinary cat and that of a leopard. Normally those sensations might be indistinguishable, but an emotional event like nearly being killed by a leopard could quickly train an animal's ability to tell the difference.